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Know How... 121 (Transcript)

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Your questions, garbage matting, the
quad copter integration, Know How is up next!

Father
Robert Ballecer: Welcome to Know How, it is the show where we build,
bend, break and upgrade. I’m Father Robert Ballecer.

Bryan
Burnett: And I’m
Bryan Burnett.

Fr.
Robert: For the
next 45, 50, 60 minutes. Oh by the way happy Thanksgiving!

Bryan: Did you fill up?

Fr.
Robert: No! I was
doing the whole Thanksgiving turkey, soup kitchen. It was fun.

Bryan: I had for Thanksgiving’s. I had a
lot to be thankful for.

Fr.
Robert: Did you get
some riding in? Did you get some driving in?

Bryan: A little bit. I got to fly my quad
copter. I didn’t get to do the lunchbox. I Only had
time for the quad copter. Enough time that I hadn’t tighten the bolts and out
on what of my props and shot off mid-flight. Fortunately, it was only about 5
feet off the ground that it was a bad nonetheless.

Fr.
Robert: At least
you didn’t destroy it. And for that you say it is a Thanksgiving miracle.

Bryan: Definitely because it was your
quad.

Fr.
Robert: Well it is
your quad now. Congratulations! You just got a quad.

Bryan: It’s that easy? I just had to crash
it?

Fr.
Robert: We had
actually got some things to be thankful about here. Specifically if you are
into space this is an exciting time. Last week NASA announced Orion. If you
haven’t been keeping up on your space news remember Orion was originally the
replacement for the space shuttle that was being built for the moon missions
which were canceled in 2010. Remember those?

Bryan: I do. And I was very disappointed
to hear that because it has been a long time since we've done anything that
ambitious in space.

Fr.
Robert: It has
been. And now, I love the saddle. I grew up with the shuttle and it was a
marvel of technology. But it was aging and it never really delivered what it
promised.

Bryan: It was supposed to be an economical
way of getting into space.

Fr.
Robert: And it was
never that. The idea is great. Take a craft that can be used over and over
again. It is going to be a lot less expensive. But the problem with the space
shuttle is that essentially every time you landed, you had to tear the thing
apart and check it. And we found out what happens when you don’t. If you look
at Orion and the funny thing about this is that it looks a lot like the Apollo
capsule. We are going back to this whole simple is better. Make it a capsule.
It is not really reusable but at the same time it is lot less expensive. There
are a lot fewer things that can go wrong and you use proven boosters to get it
up into orbit.

Bryan: I like that. Especially with
something that complex and so many things can go wrong. I think the kiss mentality
is good, keep it simple stupid.

Fr.
Robert: They were
supposed to launch a test flight today. It got described. Actually I was
excited because right about now if it had launched what it was supposed to
initiative been on its way back to reentry and we could actually done live views. But they had to scrub it because they had
some issues.

Bryan: They wanted to watch this show
instead.

Fr.
Robert: Yeah. There
are a bunch of people at NASA who are like Whoa, Know How is one today we can’t
be launching anything.

Bryan: I know everyone out there is very
disappointed but tune in to Twit.tv and you might be happy again.

Fr.
Robert: There are a
few things that I really like about this. It is going to be launched on the
back of the Delta four heavy launch vehicle. If you
look at it, it is not like the old Saturn’s that was like big Roman candles.
This actually has boosters next to it. It’s futuristic. It was supposed to do a
4 1/2 hour flight. It was going to do two laps around the earth. The first lap
was something like 270 miles. Essentially where the ISS is. It was an elliptical orbit and then the next one was going to be three times
out from now. The idea was to see how does it handle? But the big test was
going to be how does the heat shield bear up on reentry? Because it was going
to get up to about 4000° before it splashes into the Pacific.

Bryan: Is this going to be manned?

Fr.
Robert: No. Totally unmanned. These are still early days. A very exciting announcement. First time you are going to
see a man mission is 2021. The earliest. It is going
to take a while and people are even wondering whether
or not it’s actually going to happen. Because, by that time
this thing will cost between 18 and $21 billion for the program. But we
need something. We have no space craft that is capable of putting humans into
space. We’ve got some private space vehicles but aside from the one that Moscow
is putting together, the Dragon, which is not yet been proven either, we have
nothing that will carry humans into space. We can carry cargo but we cannot get
it up to orbits where we need to do actual space exploration.

Bryan: I forget what the exact date was
but anyone born after 1938 or something like that hasn’t been on the moon.

Fr.
Robert: It has been
a while.

Bryan: So if you were born after 1938,
nobody has been on the moon since then.

Fr.
Robert: But you
know what is not sad? Feedback! Let’s talk a little about what our viewers have
been asking for the last couple of weeks that we have been off the air.

Bryan: The first feedback segment that we
are going to take a look at is choosing your electronic speed controller. This
is from Garrett from Milwaukee. “Thanks Padre and Bryan for your episode on
Quad Copters. I’d like to know about the attack rather than just assembling it.
I’ve got all of my components except for the electronic speed controllers and I
am stuck. I’ve seen dozens of models on Amazon and I don’t know which is the right one to get. I’m using an EX2213 980 KV motors. I’m
considering the hobby powered 30 amp for about $17.95,
which isn’t that bad. Will that work for me? Is there a better one that I
should be looking at? Is there really a difference between ESC’s?”

Fr.
Robert: Garrett,
this is actually a very good question. We didn't get to this at the end of the
last episode because we ran out of time. There is a huge difference. This is
not one of those things that you want to trust to just any ESC. I know it is
confusing because there are actually very few beginner tutorials on the
Internet. Most people just assume that you understand what parts you need to
get. ESC’s are the things that go on to your quad and connect your motor to the
battery and flight controller. This is essentially what you are looking at.
I've got four quad copters. You could go to Amazon and type in electric speed
controller and you can find the one from hobby power. Which are great, but here
is the thing. Those were designed for planes and helicopters. These are
specifically designed for quad copters. You can use set hobby power, you can
use a hobby power 30 amp that you buy for $70.95 for a quad copter. But there
are a couple of things wrong with it. The speed controller for playing for a
helicopter refreshes its position rate. So they find out from the controller
what throttle they should be at. And those are going to refresh at about 400
times a second. They will check to see and might the right throttle. The
problem is, the higher you go the more resolution you get. The
more finite resolution. Otherwise if you are moving your stick and you
move it in between those refreshes you won’t respond immediately. 400 is a
little low, 500 is a theoretical max. Because the width of the pulse is 2 ms.So you can have five of those
a second. The speed controllers that are specifically designed for quad copters
run at 500 rather than 400.

Bryan:Which makes sense
because it is a very fine motor movement.

Fr.
Robert: Right.
Think about it. On a plane if you don’t have immediate throttle response, that is okay because you are still generating
lift. That is not the thing that is keeping the plane in the air. Where, on a
quad it is all about the thrust. If anything is unbalanced it is going to wobble
and fall out of the air. You get really bad things because there is nothing
else that is keeping it in the sky.

Bryan: If one prop becomes loose it
crashes. So I am guessing you wouldn’t want to mix and match.

Fr.
Robert: No. That is
horrible. A really really horrible
idea. I have seen it where people have one big controller and three
small ones. No. Don’t do it. There is another thing; the speed controllers that
they use for planes and helicopters have an averaging function. The idea is,
let’s say I am using my transmitter on a quad copter and I want to go from zero
to full. I can do that and that is fine. On a helicopter you don’t want to do
that because it will actually grind up the gears. Because of
the torque. It will just crank it. So for planes and for helicopters it
will average the input to give it a curve. Which is great
because you don’t want to stress the plain error frame and you don’t want to
grind out the transmission on a helicopter. But again, on a quad copter
which has no transmission, this is direct drive, you
want it to go to 100 immediately. Especially once you start doing acrobatic
type stuff. So, the thing you want to look for and this is important. You want
to look for something called Simon K firmware. He is a programmer who went into
the firmware for electronic speed controllers and he removed all the stuff that
was useful for planes or helicopters but useless for quad copters. He got rid
of the averaging function and he upped the refresh time to 500 Hz. To the theoretical limit. So they respond really, really
well. Right now, my source for Simon K is readytoflyquads.com. I’ve mentioning them a lot
just because at the very beginning when I started doing this, I was buying
stuff off of Amazon and I couldn’t figure out why it was oscillating and why
can’t I hold this thing straight. It was software. And Paul Baxter over at readytoflyquads.com he actually reached out to me and told me it was my speed controllers. I
replaced the speed report is and it was done.

Bryan: So, if you have a speed controller
can you reset the firmware? Or is it something that…

Fr.
Robert: You can.
But it is kind of a pain in the butt. And not all speed controllers can be
reset properly. Some speed controllers when you reset will break. Or they will
update and then they act funny. And it could just be because the components on
the board are really good. For example, if you bump up the refresh rate but the
board is not capable of really handling the refresh rate it is going to be bad.